My daily driver is a '62 Suburban. I've gone 'round and 'round thinking about an auto overdrive or a manual trans. I've decided on the manual trans. Now the question becomes this: The truck will have a warmed 350 engine. The trans in it is a truck 4-spd, with Granny Low. I was told the rear end is a 4.11; I haven't verified, but we'll ***ume it is. I will be getting a Chevy/Chrysler A833 4spd OD manual trans. It'll bolt up, just have to move the shifter hole and shorten the driveshaft. On another site, I was given the gear ratios for each trans--I haven't verified these either, but everything seems correct from other things I've picked up about these transmissions over the years. What I'm wondering is this: For a daily driver/tow rig, will I be better off with the Granny Low 4spd and 3.08 gears in the rear end (maybe something just a tick higher), or the A833 with 4.11 or 3.93 gears and it's final drive ratio of .73:1 overdrive? The Granny trans is basically a 3spd--you never use 1st unless you want to pull a building off it's foundation or something. However, with 3.08 gears, it could be more useful, especially when pulling a trailer. There is a VERY steep split between 1st and 2nd on this trans, and a pretty good split between 2nd and 3rd. However, there is also a really steep split between 1st and 2nd on the A833. They should both be considered 3spd transmissions: One has an overdrive and makes up for it on the back end, the other has a rediculous 1st gear and can make use of highway gears in the rear end. From a daily driving standpoint, going up hills with a trailer, etc. etc. etc., of these two choices what would be the better? Below is my ratio chart for the gearing, and numbers indicating splits with different gear ratios: Granny 4spd Gears: x........... w/4.10 w/3.73 w/3.55 w/3.23 w/3.08 1st: 7.05 28.97 26.29 25.02 22.77 21.74 2nd: 3.58 14.67 13.35 12.70 11.56 11.02 3rd: 1.71 7.01 6.78 6.07 5.52 5.26 4th: 1.00 4.10 3.73 3.55 3.23 3.08 A833 4spd OD 1st: 3.09 12.66 11.52 10.96 2nd: 1.67 6.84 6.22 5.92 3rd: 1.00 4.10 3.73 3.55 4th: .73 OD 2.99 2.72 2.59 I don't think it would be possible to run anything smaller than a 3.23 rear gear ratio with the A833, and still tow with it. If I've done the math correctly, on the Granny Trans, the gear split from 2nd to 3rd is .47, or a 53% change in rpm, and .58 from 3rd to 4th, or a 42% change in rpm. That steep 1-2 shift is "only" 50% The A833 splits are .54, or a 46% drop in rpm from 1st to 2nd, and .59 (41% rpm drop) from 2nd to 3rd, and then .73 into Overdrive, good for a 27% drop in engine rpm. (To arrive at those numbers, using the Granny 2/3 shift numbers as the example, I divided 1.67 by 3.09 to get .47, and then subtracted that from 100% to arrive at my percentage of change in rpm as 53%. I THINK that's the way it needs to be done, but am not sure I've done it correctly. And I can't find my Auto Math Handbook right now) A long, odd-ball question for sure, but I'd like to get some input from anybody who might have driven something similar, or sees any problems from a daily driver or tow rig stand point. As it is right now, I drive the Granny 2nd-to-4th, ignoring 1st unless I have a tree stump to pull. It's not a truck that will jack-rabbit start, so I'm worried about bogging going up hills, especially with a load, and having to really wind it out between gears and/or bogging between gears. -Brad The gear chart doesn't want to transfer cleanly and in straight columns to make it easier to read. The "w/Number" is the rear gear ratio. The numbers below that are what I figured with the trans ratio TIMES the gear ratio. I did not continue the A833 column past 3.23 rear gears.
about the rearend...should be a 3.90 if it's an original drop out pumpkin type. If so, you need to do some work and swap out the whole rear to get a 3.08ish ratio...I believe you could do this with a mid-late 60s truck rear, with 70s gears in it, if you're keeping it six lug. There are some issues with panhard bar, and maybe some other things too. If you keep the original rear, the 833 looks like a good bet. If you keep the granny box, you probably want to do some rearend work to make the truck pleasant to drive on the freeway. But 3.0s (or overdrive with 3.90s) is kind of iffy for towing much weight with a small block if you have to deal with a lot of hills.
hey guys, this is my first post, i'm ian. i daily drive a 1990 chevy half-ton 2wd with a 4.3v6 / sm465 and 3.08 rear end on ~29" tires. it's a good truck. it's works good. i wish i had overdrive though. low gear is great for towing trailers. you harldy have to slip the clutch. it's non-snchro though so sometimes you have to wiggle it a bit to get it to go in. what is stopping you from using an nv4500 ******? it has a low gear and overdrive (0.70) no overdrive and a 4.10 rearend is gonna make you cry on the highway. it would have lots of accelereation though. i know the ****** has some gaps between the gears but it's not a corvette, just keep giving it gas and shifting till you get to where you want to be. with a 465, 3.08s and 29" tires you'll be turning the same RPM's at 65 mph as you would be turning at 80mph with a nv4500, 3.73s and 31s.
hi Ian... I think the motor mount, clutch linkage and frame design on the 60-62 trucks are a big deterrent to using one of those late model truck ******s.
My daily driver is a '69 F100 that I occasionally tow my trailers with. It has a 302 (2bbl), a T-18 trans (4spd with a really low 1st gear), and an axle ratio of 2.75 in the ford 9" (originally was 3.50). It runs 2500 RPM at 75mph, much better than with the original gears. Towing is acceptable with this configuration, and I am talking about towing 3000~6000# (including trailer) around town and for relatively short distances. If I need to tow a really heavy load on the expressway or for any long distance I use my F350 4WD... Don't forget about having enough brakes to stop what you are towing, but that's another topic... The thing to remember about pulling loads up hills is that horsepower is just as important as having gears to maintain speed. We used to have a C-65 tandem axle dump truck with a 427 engine, a 5spd trans and a 4spd auxilliary trans (5 x 4 = 20 speeds), and it always ran out of speed (power) when going up hills loaded. Empty, that truck would really move. If I were you, I would change the rear axle ratio to 2.73 or 3.08, and save that A-833 OD trans for a (light) hot rod. Keep in mind that Chrysler used lots of A-833's in their 1/2 ton 2WD Dodge trucks, but never in anything bigger.
think about it this way: Both of these transmissions are effectively three speeds - one's got a gear below 1st, and the other's got a gear above 3rd...other than that, the intermediate ratios are fairly close (3.58 vs. 3.09, 1.71 vs 1.67, 1.00 vs. 1.00). With this in mind, you can gear the truck pretty much any way you choose by picking the 'right' final drive ratio. I'm not a big fan of tall gears - especially when towing. Tall gears and a manual trans mean there will be times you're 'between' gears - O/D is too tall, and 4th is too short for that light grade at freeway speeds, for example. If it were my nickel - you'd be better off with a shorter gear and the OD trans - the combo would have more gear 'overlap (overlap being defined as the powerband vs speed in any given gear) than the tall ratio would. The engine build has to be factored in, too. Cam selection will be important; a tow grind can make big torque down low - and that's whatcha need. Make sure you select a cam that makes power from 2000-4400 RPM; you don't need any more spin that 4400 in a tow vehicle. finally- check the torque ratings of both transes. As an inveterate blower of transmissions (6 in the last three years) you DON'T want to run the trans near its rated limit for extended periods; the higher TQ rating would last longer - trust me on that!
The rear in the truck is a Dana 44 swapped in by a previous owner. I'd be interested to see what it originally came out of, because it looks like the panhard bar and trailing arm mounts are stock OE welds. That owner traded a set of really nice cab clearance lights to a junk yard owner for the rear. I found pics from him on a defunct website, and it looks like a direct swap. He wasn't real mechanically inclined, so he wasn't there fabricating it. It's a 6-lug axle rear. The shortblock I have for it is a 350, 030-over, 9.5:1 pistons, and too much cam. It has a 292H-10 Comp cam in it, and I have a new 286 cam for it. If that's too much, I'll get a different one. Heads are stock castings (forget the number right now) that have had 2.02/1.60 valve put in the right way, completely unshrouded. I've got full roller 1.5 rockers, or roller tip 1.6 COMP Magnum rockers for it (with the correct valve springs). Intake is a dated, but period-correct Edelbrock C4B, with a Carter/Edelbrock carb on it. HEI Ignition, and I'll put cast iron 2.5-inch exhaust manifolds on. Right now, it has a tired 283 2bbl, and it keeps up with I-285 Atlanta traffic. In the left lane. I p*** people in the right lane. Yes, it screams. I don't have a tach, so I have no idea what the rpm is. And I'm scared to do the math! Tires are tall. The new engine should be pretty stout. When I tow with it, it'll be a 5x8 enclosed trailer with a few hundred pounds of swap meet gear in it (PA system, two EZup tents, metal fence posts, chairs, tables, supplies, etc.) once a month. My race car will probably come in around 3200 pounds, and my tandem axle trailer is 1800lbs empty. Locally, it's pretty flat between here and the drag strip. But I do have visions of going to Mokan, York PA and Columbus OH next year. So, given that, (and it isn't going to be ideal, I know), would the overdrive with present gears be better, or 4spd Granny ****** with 3.23 or 3.08 be better? And yes, bellhousing/engine mounts/no trans cross member is what's limiting me to these transmission choices. A T5 would also probably work, but I've got the two I'm talking about already. My Suburban is a 1/2-ton, and I have kept in mind that the A833 was put in half-ton Chevy and Dodge trucks, so while it may not be very strong, it was ***umed by the designers that some people would use them to tow. Then again, they also put them in Slant 6 Dusters... -Brad
I have towed extensively with two Chevrolet Pick-ups. Here's what I can offer: Presently, I have a 2000 Chevy 3/4 ton truck with the tall tires and a 4.10 R&P. This truck tows great in high gear, hardly ever shifts and can even tow in overdrive on the highway. It has an automatic with 3 gears plus overdrive. At 65 miles per hour, the engine turns about 2200 rpm in overdrive, about 2600 in drive. The truck I had previously was a 1987 Chevy 1/2 ton. It had a automatic with overdrive too. The original gear was 2.73 R&P. The truck towed terrible with that gear. It was almost always in second gear unless you were highway cruising. The transmission had to shift a lot and the RPM was always too high. It consumed a tremendous amount of fuel when towing because the engine had to work so hard. I switched to a 3.42 R&P and the truck towed beautifully in high gear. It now hardly ever need to shift, and fuel consumption when towing was much better. You still didn't want to tow in overdrive though. As far as regular driving, it worked out good because now the overdrive in the transmission was useable. With the 2.73 the truck hardly ever needed to be put into overdrive...and when you did, it would contantly shift in and out. With the 3.42 the combination seemed right. All that being said, if I were you, I'd keep the 4.11 rear and run the overdrive transmission with tall tires. I think you'll find that towing-wise, you'll be happy with the performance. Daily driving wise, the 4.11 will work out pretty good with overdrive to keep RPM in check.
Brad--it looks to me like a toss-up....either you deal with swapping rearend gears and leave the trans alone, or you deal with swapping the trans and leave the rearend alone. Do you have a decent shifter for the 833? have you double checked to make sure it will fit the chevy bellhousing and clutch? do you have a driveshaft yoke for it? will the parking brake linkage clear the trans/shifter? Did you double check to make sure the rear is a Dana 44? should have the number 44 cast into the center housing, either on top or next to the cover plate.
The questions about the park brake linkage are an EXCELLENT point--one I hadn't thought of. I do have a shifter for the trans--was going to send it to Hurst for a rebuild. It will fit the Chevy truck bellhousing: There are two; one has a Mopar mounting footprint and requires the retooled OE Chevy aluminum bellhousing, th other case actually does have the Chevy footprint. I actually have both. It has the Chevy clutch spline count and input shaft length. I would need to source a yoke. I have not double checked my rear end, just looked at the rear cover and visually id'd it as a 44. We also have a bunch of 4x4 guys at work here, and they took a look and said "yup, Dana 44." I'll look for the numbers cast into it tonight. It is a posi carrier though, according to the pics on the website from when the guy put it in. The clutches are worn though, so it really need to be rebuilt anyway. -Brad
The reason I asked about the rearend is that I have an original 59 truck 1/2 ton Dana 40 rearend, it was the posi option, and it looks just like a 44 from the outside...but it has different size bearings and different splines inside.
I've built a couple of trucks for Pop - and shorter gears have always been better for towing. One was a 360 inna Dodge truck - that had 3.54's turning 16.5" Budd split rims; went with a short duration cam, W2 heads and a dual plane manifold. Pop could run the camper, tow the boat, and still charge up hills at 80. the 351 that replaced it got a tow cam & headers, but retained the taller stock gear. The truck was a pig - both from a power standpoint and a fuel standpoint. I think it had 3.23's. Current truck has a stock drivetrain (300 HP bowtie motor) and 3.73's (I think) no mods; tows great AND gets good MPG. As far as I'm concerned, 3.08's are for a non-towing highway vehicle without overdrive. Tall ge****ts were an offshoot of early CAFE regulations; a tall gear was an easy way to make CAFE requirements with minimal powertrain mods. now that OD transes and lockup torque convertors are common, gear ratios are creeping back up again, with 3.55's, 3.73's, and 3.90's fairly common.
There are a lot of variables....and 3.08s can work ok for towing. I ran the stock 3.73s in my 66 suburban for a long time, behind a 454/th400, it towed fine but highway speed was effectively limited to about 65 mph. Before I sold it I swapped in an old 402 and some 3.07 gears, it still towed ok and was more pleasant on the highway. You need some torque to pull those gears...and also pinging can be a problem with more than 8.5:1 compression. 3.23 or 3.54 wold probably be a better choice.
I agree with the variable comment; tall gears work when you've got torque out the *** - like with a BB motor. Had tall gears behind a low compression 360 inna Dodge van, and it was a ping-monster; motor started to go soft (compression drop) at 110K miles. Behind a 350? short gears and an OD, if at all possible. Best of both worlds. As for a cam - something like a 272 duration to keep the motor mid TQ band at freeway speeds. I drove a mod-motored (5.4) truck recently, and the shift map was programmed to make that thing spin at 4500+ every time you tipped past 20% on the throttle - that's just too busy for towning, IMHO. No torque.
my 406 chey powered 1960 dodge pu runs and tows just about perfect for myself. i run a 325 9" rear and a 700R4 od. this gives me a 325 gear to tow a heavy load w/ in direct and some where around 2.50 to cruise with. a lot a people will say the 2.50 in od is to much. i would say that most have not tried it and are running to low of gears.
I've got an '89 Chevy 1/2 ton ex-cab truck that I use as a daily driver and occasional tow vehicle. Its got an extremely mild 350 in it (which is MUCH more powerful in this setup than the original 4.3), 5 speed, and what I believe are 3.08 gears in the rear - in any case, they're stockers. What I notice about my truck, and I've heard this with many other 5 speeds as well, is that you're not supposed to tow in overdrive (5th gear). I know you're not supposed to tow in overdrive on the automatics, but I'm pretty sure its not great to do with the 5 speed. At any rate, when I'm driving my truck pulling the trailer (18' dovetail car trailer - approx 2000# empty), I can barely pull in 5th gear. Give me even a mild hill, and I'm forced to drop into 4th and power on. Of course, in 4th gear I notice no drops in power to speak of, and just a little more poke at the go pedal and she'll scream on like its nobody's business! Either way, I thought I'd add that into the mix. Isn't the typical later model GM 5 speed a lighter duty trans?
3.25 x .70 = 2.27 so it's even longer than you thought. I have run 2.75s in my 55 for years....nice gear...having a torquey motor is a very helpful. Right now it has 3.25s in it and highway driving is a bit loud.
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